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White Hake

White Hake. Base Similar to 2002 VPA results FractionSamples Introduces uncertainty in age-length key AgeError Ageing imprecise FractionandAgeError Purpose: test models under high ageing uncertainty and bias. White hake basic setup. Years 1989-2001 (12 years) Ages 1-30, 9+

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White Hake

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  1. White Hake • Base • Similar to 2002 VPA results • FractionSamples • Introduces uncertainty in age-length key • AgeError • Ageing imprecise • FractionandAgeError • Purpose: test models under high ageing uncertainty and bias

  2. White hake basic setup • Years 1989-2001 (12 years) • Ages 1-30, 9+ • Lengths 1-200 cm • 2 market categories • 3 surveys • (CVs vary by age, 20%-50%) • CV on landings 5% • Growth stdevs 5.0 initial, 1.0 projection • Von B params 189, 0.081, 0.062 • 50% Mature ~35 cm • Selectivity flat-topped, 50% selected 39 cm • M = 0.2 • F high all years (0.5-2.1)

  3. White hake test cases • Fractionsamples • 40% of lengths used to create ALK • AgeError • Adds uncertainty but not much bias

  4. White Hake

  5. White Hake

  6. AIM

  7. White Hake

  8. SCALE

  9. White Hake

  10. VPA (SSB)

  11. VPA (FAA)

  12. White Hake

  13. ASAP

  14. VPA vs ASAP NAA

  15. VPA vs ASAP NAA

  16. Precision (SSB and F) • AIM: ~ 0.1-0.2, did not vary by case • SCALE: ~0.1, did not vary by case • VPA*: <0.2 (poor ages>7) • ASAP: ~0.05, did not vary *VPA CVs are for age-specific SSB, F

  17. White Hake Conclusions • Models that do not fit age data (AIM, SCALE) were robust to aging errors (assuming correct von B for SCALE) • Bias pattern similar for VPA and ASAP, but magnitude was far less for ASAP

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